Multilayer ceramic capacitor and board having the same

ABSTRACT

A multilayer ceramic capacitor (MLCC) includes a body including first dielectric layers and second dielectric layers, the body including first to sixth surfaces, a second surface, a third surface, a fourth surface, a fifth surface and a sixth surface; first internal electrodes disposed on the first dielectric layers, exposed to the third surface, the fifth surface, and the sixth surface, and spaced apart from the fourth surface by first spaces; second internal electrodes disposed on the second dielectric layers to oppose the first internal electrodes with the first dielectric layers or the second dielectric layers interposed therebetween, exposed to the fourth surface, the fifth surface, and the sixth surface, and spaced apart from the third surface by second spaces; first dielectric patterns disposed in at least a portion of the first spaces, and second dielectric patterns disposed in at least a portion of the second spaces; and lateral insulating layers.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of priority to Korean PatentApplication Nos. 10-2017-0048049 filed on Apr. 13, 2017 and10-2017-0071512 filed on Jun. 8, 2017 with the Korean IntellectualProperty Office, the entirety of which is incorporated herein byreference.

TECHNICAL FIELD

The present disclosure relates to a multilayer ceramic capacitor and aboard having the same.

BACKGROUND

Capacitors are devices able to store electricity. When a voltage isapplied to two opposing electrodes of a capacitor, the respectiveelectrodes of the capacitor are charged with electricity. When a directcurrent (DC) voltage is applied to the electrodes of the capacitor, DCcurrent flows into the capacitor while electricity is stored therein.However, when electricity storage is completed, the DC current no longerflows thereinto. In contrast, when an alternating current (AC) voltageis applied to the electrodes, AC current continues to flow into thecapacitor while the polarities of the electrodes alternate with eachother.

According to types of insulators provided between the electrodes, suchcapacitors may be divided into various types: an aluminum electrolyticcapacitor having electrodes formed of aluminum and having a thin oxidelayer between the electrodes; a tantalum capacitor using tantalum as anelectrode material; a ceramic capacitor using a high-k dielectric, suchas titanium barium, between electrodes; a multilayer ceramic capacitor(MLCC) provided as a dielectric between electrodes using a high-k-basedceramic as a multilayer structure; and a film capacitor using apolystyrene film provided as a dielectric between electrodes.

Among these capacitors, the MLCC may have excellent temperature andfrequency characteristics and may be implemented to have a compact sizeto thus be applied for use in various fields, such as high-frequencycircuits.

MLCCs, according to the related art, have a laminate formed by stackinga plurality of dielectric sheets, external electrodes formed on externalsurfaces of the laminate to have different polarities, and internalelectrodes alternately stacked inside the laminate to be electricallyconnected to the external electrodes, respectively.

In recent years, with electronic products being formed to have a compactsize and high integration, a lot of research into the implementation ofcompact size and high integration in MLCCs has been conducted. Inparticular, in the case of MLCCs, various attempts have been made toimprove the connectivity of internal electrodes while thinning andhighly stacking dielectric layers, in order to achieve high capacity andcompact size in MLCCs.

Especially, it has become more important to ensure the reliability ofproducts in which thin-film dielectric layers and internal electrodesare highly stacked. As the stacking number of dielectric layers andinternal electrodes is increased, there may be an increase in an amountof step portions formed due to a difference in thicknesses between oneportion, such as a central portion of the MLCC, in which the internalelectrodes and the dielectric layers are stacked, and another portion,such as an edge portion (or margin portion), in which some of theinternal electrodes formed in the one portion may not be formed. Suchstep portions may cause the end portions of internal electrodes to bebent, owing to the transverse elongation of dielectric layers, in adensification process of pressing MLCC bodies.

That is, the end portions of internal electrodes may be curved when someportions of the dielectric layers reposition to fill the step portions,and margin portions may remove empty space, formed by the step portion,by the depression of covers and a reduction in the margin width.Capacity layers may also be elongated by the margin width reduced byremoving the empty space in the margin. Such structurally irregularelongation of internal electrodes may reduce the characteristics ofMLCCs, such as breakdown voltage (BDV) characteristics.

The occurrence of the step portion, as described above, may be a problemboth in a first direction, perpendicular to the stacking direction ofthe internal electrodes and the dielectric layers of the MLCCs, and in asecond direction, perpendicular to the first direction and perpendicularto the stacking direction. Thus, a need exists for a solution to solvethis problem.

SUMMARY

An aspect of the present disclosure may provide a multilayer ceramiccapacitor (MLCC) having a structure capable of addressing the issue of astep portion formed by a difference in thicknesses between differentportions of a laminate including a dielectric layer and an internalelectrode.

According to an aspect of the present disclosure, a multilayer ceramiccapacitor (MLCC) may include: a body including first dielectric layersand second dielectric layers, the body including a first surface and asecond surface opposing each other in a stacking direction along whichthe first and second dielectric layers are stacked, a third surface anda fourth surface connected to the first surface and the second surfaceand opposing each other, and a fifth surface and a sixth surfaceconnected to the first surface, the second surface, the third surface,and the fourth surface and opposing each other; first internalelectrodes disposed on the first dielectric layers, exposed to the thirdsurface, the fifth surface, and the sixth surface, and spaced apart fromthe fourth surface by first spaces; second internal electrodes disposedon the second dielectric layers to oppose the first internal electrodeswith the first dielectric layers or the second dielectric layersinterposed therebetween, exposed to the fourth surface, the fifthsurface, and the sixth surface, and spaced apart from the third surfaceby second spaces; first dielectric patterns disposed in at least aportion of the first spaces, and second dielectric patterns disposed inat least a portion of the second spaces; and lateral insulating layersdisposed on the fifth surface and the sixth surface of the body.

BRIEF DESCRIPTION OF DRAWINGS

The above and other aspects, features, and advantages of the presentdisclosure will be more clearly understood from the following detaileddescription, taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 illustrates a schematic perspective view of a multilayer ceramiccapacitor (MLCC) according to an exemplary embodiment;

FIG. 2 illustrates a schematic perspective view of a body of an MLCCaccording to an exemplary embodiment;

FIG. 3 illustrates a schematic cross-sectional view taken along lineI-I′ of FIG. 1;

FIG. 4 illustrates a schematic cross-sectional view taken along lineII-II′ of FIG. 1;

FIG. 5A illustrates a schematic cross-sectional view of an MLCCaccording to a comparative example, and FIG. 5B illustrates an enlargedview of a cross section of an end portion of an MLCC according to acomparative example in a length direction, and depicts a measureddeformation angle of an internal electrode;

FIG. 6A illustrates a schematic cross-sectional view of an MLCCaccording to an exemplary embodiment, and FIG. 6B illustrates anenlarged view of a cross section of an end portion of an MLCC accordingto an exemplary embodiment in a length direction, and depicts a measureddeformation angle of an internal electrode;

FIG. 7 is an image of a cross section of an MLCC according to acomparative example having a margin portion, and depicts a location P inwhich breakdown voltage (BDV) characteristics are poor;

FIGS. 8A and 8B illustrate a gap between an internal electrode and adielectric pattern disposed on a ceramic sheet, before a stackingprocess to form a body, during manufacturing an MLCC;

FIGS. 9A and 9B illustrate the shape of an internal electrode and adielectric pattern printed on a ceramic sheet, before a stacking processto forma body, during manufacturing an MLCC;

FIGS. 10A and 10B illustrate schematic plan views of a first internalelectrode and a second internal electrode of an MLCC according toanother exemplary embodiment; and

FIG. 11 illustrates a schematic perspective view of a board having anMLCC according to another exemplary embodiment.

DETAILED DESCRIPTION

Hereinafter, embodiments of the present disclosure will be describedwith reference to the attached drawings.

The present disclosure may, however, be exemplified in many differentforms and should not be construed as being limited to the specificembodiments set forth herein. Rather, these embodiments are provided sothat this disclosure will be thorough and complete, and will fullyconvey the scope of the disclosure to those skilled in the art.

Throughout the specification, it will be understood that when anelement, such as a layer, region or wafer (substrate), is referred to asbeing “on,” “connected to,” or “coupled to” another element, it can bedirectly “on,” “connected to,” or “coupled to” the other element, orother elements intervening therebetween may be present. In contrast,when an element is referred to as being “directly on,” “directlyconnected to,” or “directly coupled to” another element, there may be noother elements or layers intervening therebetween. Like numerals referto like elements throughout. As used herein, the term “and/or” includesany and all combinations of one or more of the associated, listed items.

It will be apparent that, although the terms ‘first,’ ‘second,’ ‘third,’etc. may be used herein to describe various members, components,regions, layers and/or sections, these members, components, regions,layers and/or sections should not be limited by these terms. These termsare only used to distinguish one member, component, region, layer orsection from another region, layer or section. Thus, a first member,component, region, layer or section discussed below could be termed asecond member, component, region, layer or section without departingfrom the teachings of the exemplary embodiments.

Spatially relative terms, such as “above,” “upper,” “below,” and “lower”or the like, may be used herein for ease of description to describe oneelement's relationship relative to another element(s), as shown in thefigures. It will be understood that spatially relative terms areintended to encompass different orientations of the device in use oroperation, in addition to the orientation depicted in the figures. Forexample, if the device in the figures is turned over, elements describedas “above,” or “upper” relative to other elements would then be oriented“below,” or “lower” relative to the other elements or features. Thus,the term “above” can encompass both the above and below orientations,depending on a particular directional orientation of the figures. Thedevice may be otherwise oriented (rotated 90 degrees or at otherorientations) and the spatially relative descriptors used herein may beinterpreted accordingly.

The terminology used herein describes particular embodiments only, andthe present disclosure is not limited thereby. As used herein, thesingular forms “a,” “an,” and “the” are intended to include the pluralforms as well, unless the context clearly indicates otherwise. It willbe further understood that the terms “comprises,” and/or “comprising”when used in this specification, specify the presence of statedfeatures, integers, steps, operations, members, elements, and/or groupsthereof, but do not preclude the presence or addition of one or moreother features, integers, steps, operations, members, elements, and/orgroups thereof.

Hereinafter, embodiments of the present disclosure will be describedwith reference to schematic views illustrating embodiments of thepresent disclosure. In the drawings, for example, due to manufacturingtechniques and/or tolerances, modifications of the shape shown may beestimated. Thus, embodiments of the present disclosure should not beconstrued as being limited to the particular shapes of regions shownherein, for example, to include a change in shape resulting frommanufacturing. The following embodiments may also be constituted aloneor as a combination of several or all thereof.

The contents of the present disclosure described below may have avariety of configurations, and only a required configuration is proposedherein, but the present disclosure is not limited thereto.

Multilayer Ceramic Capacitor (MLCC)

FIG. 1 illustrates a schematic cross-sectional view of an MLCC 100according to an exemplary embodiment, and FIG. 2 illustrates a schematicperspective view of a body 110 of the MLCC 100 according to an exemplaryembodiment. FIG. 3 illustrates a schematic cross-sectional view takenalong line I-I′ of FIG. 1, and FIG. 4 illustrates a schematiccross-sectional view taken along line II-II′ of FIG. 1.

Referring to FIGS. 1 through 4, the MLCC 100 according to an exemplaryembodiment will be described hereinafter.

The MLCC 100, according to the exemplary embodiment, may include thebody 110 having a plurality of first and second dielectric layers 111 aand 111 b stacked therein, a first external electrode 151, and a secondexternal electrode 152.

The body 110 may be formed by stacking the first and second dielectriclayers 111 a and 111 b in a thickness direction thereof and firing thestacked first and second dielectric layers 111 a and 111 b. The numberof the first and second dielectric layers 111 a and 111 b may beadjusted appropriately. For example, tens to hundreds of first andsecond dielectric layers 111 a and 111 b, on each of which one internalelectrode is disposed, may be stacked. The respective first and seconddielectric layers 111 a and 111 b, adjacent to each other, of the body110 may be integrated to the extent that boundaries between the firstand second dielectric layers 111 a and 111 b are difficult to identify.In addition, the body 110 may have a hexahedral shape, but the shape ofthe body 110 is not limited thereto.

When the body 110 has the hexahedral shape, the body 110 may include afirst surface 1 and a second surface 2 opposing each other, a thirdsurface 3 and a fourth surface 4 connected to the first surface 1 andthe second surface 2 and opposing each other, and a fifth surface 5 anda sixth surface 6 connected to the first surface 1, the second surface2, the third surface 3, and the fourth surface 4 and opposing eachother.

In an exemplary embodiment, the stacking direction may be referred to asa thickness direction or a first direction Z, a direction, in which thethird surface 3 and the fourth surface 4 are formed, may be referred toas a length direction or a second direction X, and a direction, in whichthe fifth surface 5 and the sixth surface 6 are formed, may be referredto as a width direction or a third direction Y.

The body 110 may have upper and lower cover layers 113 and 112 formed onan upper surface of an uppermost internal electrode and a lower surfaceof a lowermost internal electrode to have a certain thickness. The uppercover layer 113 and the lower cover layer 112 may include the samecomposition as the first and second dielectric layers 111 a and 111 b,and may be formed by stacking at least one dielectric layer, having nointernal electrode, on each of the upper surface of the uppermostinternal electrode and the lower surface of the lowermost internalelectrode.

The first and second dielectric layers 111 a and 111 b may include ahigh-k ceramic material, for example, a barium titanate (BaTiO₃)-basedceramic powder or the like, but the present disclosure is not limitedthereto. Examples of the BaTiO₃-based ceramic powder may include(Ba_(1-x)Ca_(x)) TiO₃, Ba(Ti_(1-y)Ca_(y))O₃, (Ba_(1-x)Ca_(x))(Ti_(1-y)Zr_(y))O₃, or Ba(Ti_(1-y)Zr_(y))O₃, in which calcium (Ca),zirconium (Zr), or the like is partially dissolved in BaTiO₃, but thepresent disclosure is not limited thereto. In addition, the first andsecond dielectric layers 111 a and 111 b may further include at leastone of a ceramic additive, an organic solvent, a plasticizer, a binder,and a dispersant. Examples of the ceramic additive may include atransition metal oxide or carbide, a rare earth element, or magnesium(Mg) or aluminum (Al).

The first dielectric layers 111 a may have first internal electrodes 121disposed thereon. The first internal electrodes 121 may be disposed onthe first dielectric layers 111 a so as to be exposed to the thirdsurface 3, the fifth surface 5, and the sixth surface 6 of the body 110.The first internal electrodes 121 may not be exposed to the fourthsurface 4 of the body 110. The first internal electrodes 121 may bespaced apart from the fourth surface 4 by a certain distance. A space bywhich each of the first internal electrodes 121 is spaced apart from thefourth surface 4 may be defined as a first space 121′.

The second dielectric layers lllb may have second internal electrodes122 disposed thereon. The second internal electrodes 122 may be disposedon the second dielectric layers lllb so as to be exposed to the fourthsurface 4, the fifth surface 5, and the sixth surface 6 of the body 110.The first internal electrodes 121 may not be exposed to the thirdsurface 3 of the body 110. The second internal electrodes 122 may bespaced apart from the third surface 3 by a certain distance. A space bywhich each of the second internal electrodes 122 is spaced apart fromthe third surface 3 may be defined as a second space 122′.

The first and second internal electrodes 121 and 122 may be formed andstacked on a ceramic sheet for forming the first dielectric layers 111 aand the second dielectric layers 111 b, and may then be alternatelydisposed inside the body 110 in the thickness direction by beingsintered with at least one of the first and second dielectric layers 111a and 111 b interposed therebetween.

The first and second internal electrodes 121 and 122, having differentpolarities, may oppose each other in a direction in which the first andsecond dielectric layers 111 a and 111 b are stacked, and may beelectrically insulated from each other by the first and seconddielectric layers 111 a and 111 b disposed therebetween.

When an internal electrode is exposed externally of a body, shortcircuits may occur owing to the infiltration of conductive foreignsubstances into the body, and reliability of the MLCC may thus bereduced. As a result, when the internal electrode was formed on adielectric layer in the related art, the dielectric layer was formed tohave an area wider than that of the internal electrode, and a marginportion was thus formed in a remaining portion of the dielectric layer,except for a portion of the internal electrode connected to an externalelectrode. For example, the margin portion may refer to an area of adielectric in which the internal electrode is not formed. When theinternal electrode is formed on the dielectric layer in a manufacturingprocess of an MLCC, the internal electrode may have such a shape inwhich the internal electrode protrudes in a stacking direction from themargin portion. The shape may result in a step portion, and when tens tohundreds of dielectric layers are stacked, each of the dielectric layersmay be elongated and bent to fill the step portion. When the dielectriclayer is elongated, the internal electrode may also be bent together.When the internal electrode is curved or bent, BDV characteristics maydeteriorate in a curved or bent portion thereof.

Thus, the MLCC, according to an exemplary embodiment, may prevent stepportions in the width direction caused by the internal electrodes notforming in the margin portions during manufacturing, by removing themargin portions to form the fifth surface 5 and the sixth surface 6 ofthe body 110 to expose the first and second internal electrodes 121 and122. As a result, reliability of the MLCC may be increased by preventingBDV characteristics from deteriorating through avoiding the internalelectrode from being bent in the width direction.

The first internal electrodes 121 and the second internal electrodes 122may be exposed to the third surface 3 and the fourth surface 4,respectively, to be led therefrom. Thereafter, the first externalelectrode 151 may be exposed to the third surface 3 and the secondexternal electrode 152 may be exposed the fourth surface 4, and thus thefirst internal electrodes 121 and the second internal electrodes 122 maybe respectively protected by the first external electrode 151 and thesecond external electrode 152 without being exposed externally.

However, substantially all of the first internal electrodes 121 and thesecond internal electrodes 122 may be exposed to the fifth surface 5 andthe sixth surface 6, and thus the first and second internal electrodes121 and 122 may be protected by arranging additional lateral insulatinglayers 140 on the fifth surface 5 and the sixth surface 6.

The body 110 may be dipped into slurry, including ceramic, to form thelateral insulating layers 140. The slurry may include a ceramic powder,an organic binder, or an organic solvent. The ceramic powder may includea high-k material, and a material, having excellent heat resistance anddurability and a wide activating range, may be used as the ceramicpowder when forming the lateral insulating layers 140.

The type of the ceramic powder is not limited thereto. Examples of theceramic powder may include a barium titanate-based material, alead-composite perovskite material, or a strontium titanate-basedmaterial, preferably a barium titanate powder.

The organic binder may be used to ensure dispersibility of the ceramicpowder inside the slurry, but the purpose of the organic binder is notlimited thereto. Examples of the organic binder may includeethylcellulose, polyvinylbutyral, or a mixture thereof.

When the body 110 is dipped into the slurry manufactured as describedabove, a surface of the body 110 contacting the slurry may be coatedwith the slurry to form the lateral insulating layers 140. Repetition ofdipping and drying the body 110 may allow the body 110 to be coated witha desired amount of slurry to form the body 110 having a requiredthickness.

When the body 110 is dipped into the slurry, the third surface 3 and thefourth surface 4 of the body 110 may be prevented from being coated withthe slurry to form the first external electrode 151 and the secondexternal electrode 152 on the third surface 3 and the fourth surface 4.Thus, the third surface 3 and the fourth surface 4 may have a filmattached thereto and may then be dipped into the slurry, so as not to becontaminated by the slurry, but the protection manner of the thirdsurface 3 and the fourth surface 4 in the dipping is not limitedthereto. For example, a ceramic bar, which may be divided into aplurality of bodies 110 by cutting to form respective third surfaces 3and fourth surfaces 4, may be dipped in the slurry before cutting toform the respective third surfaces 3 and the fourth surfaces 4 of theplurality of bodies to allow side surfaces of the ceramic barcorresponding to respective fifth surfaces 5 and respective sixthsurfaces 6 of the plurality of bodies 110 to be coated with the slurry.After the side surfaces of the ceramic bar corresponding to therespective fifth surfaces 5 and the respective sixth surfaces 6 of theplurality of bodies 110 are coated with the slurry, a cutting processmay be performed to divide the ceramic bar to the plurality of bodies110.

By arranging the lateral insulating layers 140 on the fifth surface 5and the sixth surface 6, the conductive foreign substances may beprevented from flowing into the first and second internal electrodes 121and 122 exposed to the fifth surface 5 and the sixth surface 6.

Further, the lateral insulating layers 140 may be formed using polymer.For example, the lateral insulating layers 140 may be formed by coatinglateral surfaces of the body 110 with epoxy.

In particular, the MLCC 100, according to an exemplary embodiment, mayensure a significantly increased effective capacity area through removalof the margin portions in the width direction to form the fifth surface5 and the sixth surface 6, which the first and second internalelectrodes 121 and 122 may be exposed to, thus further increasingcapacity of the MLCC. For example, the MLCC 100, according to anexemplary embodiment, may increase a volume in which capacity thereofmay be implemented by arranging the lateral insulating layers 140 ableto prevent the infiltration of the conductive foreign substances intothe body, while having a thickness relatively reduced as compared tothat of the margin portions, on the fifth surface 5 and the sixthsurface 6 of the body 110, in lieu of the margin portions.

However, a step portion may be formed in the length direction in whichthe internal electrode is connected to the external electrode, similarlyto the step portion formed by the margin portion in the width direction.For example, even when the step portion in the width direction isprevented from being formed in the margin portion, for example, byremoving the margin portion, the step portion formed in the lengthdirection may cause BDV characteristics of the MLCC to fail to reach atarget value.

The first and second internal electrodes 121 and 122 may alternately beexposed to the third surface 3 and the fourth surface 4, both endsurfaces of the body 110 in the length direction, respectively, to beconnected to the first and second external electrode 151 and 152.

For example, the first internal electrodes 121 may be connected to onlythe first external electrode 151, and the second internal electrodes 122may only be connected to the second external electrode 152. Thus, thefirst internal electrodes 121 may be spaced apart from the fourthsurface 4 by a predetermined distance, and the second internalelectrodes 122 may be spaced apart from the third surface 3 by apredetermined distance.

When dielectric layers, on which internal electrodes having a shapedescribed above are formed, are stacked, the first and second internalelectrodes 121 and 122, alternately exposed to the third and fourthsurfaces 3 and 4, may cause a step portion to be formed in each portionof the body 110, in which only the first or second internal electrode121 or 122 is formed, in the stacking direction Z.

When tens to hundreds of dielectric layers 111 are stacked, the stepportion may cause the dielectric layers 111 to be elongated in eachportion of the body 110, in which only the first or second internalelectrode 121 or 122 is formed, in the stacking direction Z. Theelongation of the dielectric layers may cause the first internalelectrodes or the second internal electrodes in each portion of thebody, in which only the first or second internal electrode is formed, inthe stacking direction, to be bent together, as illustrated in FIGS. 5Aand 5B. BDV characteristics may primarily be reduced in a curved portionof the first or second internal electrode illustrated in FIG. 5B.

However, when the spaces between the first internal electrodes 121 andthe fourth surface 4 are defined as the first spaces 121′, firstdielectric patterns 131 may be disposed in the first spaces 121′, andwhen the spaces between the second internal electrodes 122 and the thirdsurface 3 are defined as the second spaces 122′, second dielectricpatterns 132 may be disposed in the second spaces 122′. Thus, the MLCC100, according to an exemplary embodiment, may prevent a step portionfrom being formed in the portion of the body 110, in which only thefirst or second internal electrode 121 or 122 is formed.

For example, the MLCC 100, according to an exemplary embodiment, mayinclude the first and second dielectric patterns 131 and 132 to preventthe step portion from being formed in the portion of the body 110, inwhich only the first or second internal electrode 121 or 122 is formed,thus addressing the issue of a reduction in BDV characteristics whichmay occur in the curved portion of the first or second internalelectrode 121 or 122.

Thus, the MLCC 100, according to an exemplary embodiment, may prevent areduction in BDV characteristics caused by a step portion formed in thewidth direction by removing the margin portion to form the fifth andsixth surface 5 and 6 and arranging the lateral insulating layers 140 onthe fifth and sixth surface 5 or 6, while addressing the issue of areduction in BDV characteristics caused by a step portion formed in thelength direction by preventing the step portion from being formed in theportion of the body 110, in which only the first or second internalelectrode 121 or 122 is formed, using the first and second dielectricpatterns 131 and 132, thus substantially increasing the overall BDVcharacteristics of the MLCC 100.

FIG. 5A illustrates a schematic cross-sectional view of an MLCCaccording to a comparative example, and FIG. 5B illustrates an enlargedview of a cross section of an end portion of an MLCC according to acomparative example in a length direction, and depicts a measureddeformation angle of an internal electrode.

FIG. 6A illustrates a schematic cross-sectional view of an MLCCaccording to an exemplary embodiment, and FIG. 6B illustrates anenlarged view of across section of an end portion of an MLCC accordingto an exemplary embodiment in a length direction, and depicts a measureddeformation angle of an internal electrode.

The deformation angles of the internal electrodes, illustrated in FIGS.5B and 6B, may refer to bent angles of the end portions of the internalelectrodes in a length direction X. Referring to FIG. 5B, thedeformation angle θ of the internal electrode of the MLCC according tothe comparative example, in which first and second dielectric patterns131 and 132 are not formed, may range from 25° to 50°. However,referring to FIG. 6B, the MLCC 100 according to an exemplary embodiment,in which the first and second dielectric patterns 131 and 132 are formedin the first and second spaces 121′ and 122′, respectively, the areas inwhich the first and second internal electrodes 121 and 122 are notformed, may have a deformation angle θ of 0° to 15°. Here, thedeformation angle refers to the maximum deformation angle among all ofthe deformation angles of all of the internal electrodes with respect tothe length direction X.

Such a deformation angle of the internal electrode may be determined bythe content of solids included in a ceramic paste forming the first andsecond dielectric patterns 131 and 132 and by printing thicknesses ofthe first and second dielectric patterns 131 and 132. For example, theMLCC 100, according to an exemplary embodiment, may have the first andsecond dielectric patterns 131 and 132 formed in the first and secondspaces 121′ and 122′, respectively, the spaces in which the first andsecond internal electrodes 121 and 122 are not formed, to significantlyreduce the deformation angle of the internal electrode, as compared tothe MLCC in the related art, through reducing a step portion formed bythe internal electrode, thus increasing BDV characteristics of the MLCC100.

The first and second dielectric patterns 131 and 132 may each include adielectric that may be sintered at a low temperature lower than that forsintering the first and second dielectric layers 111 a and 111 b. Asillustrated in FIG. 7, a BDV characteristics defect location P mayrepresent that a defect is concentrated at an edge portion of the chip.This shows that the BDV characteristics defect location P is focused onthe cover layer or the margin portion having a relatively low level offiring density, except for the upper surface, of the chip, most affectedby a step portion. Thus, the first and second dielectric patterns 131and 132 may be formed of a paste, including a dielectric that may besintered at the low temperature, to promote sinterability in a locationof the MLCC whose sinterability otherwise deteriorates, thus increasingreliability of the MLCC. The dielectric that may be sintered at the lowtemperature may refer to BaTiO₃, including a low-temperature-sinteredmaterial. The low-temperature-sintered material may refer to a glasscomponent, including an alkali metal, such as Na or Li. The first andsecond dielectric patterns 131 and 132 may be made of a materialdifferent from that is used to make the first and second dielectriclayers 111 b and 111 a.

FIGS. 8A and 8B illustrate a gap between an internal electrode 20 and adielectric pattern 30 disposed on a ceramic sheet, before a stackingprocess to form a body, during manufacturing an MLCC. FIGS. 9A and 9Billustrate the shape of an internal electrode 20 and a dielectricpattern 30 printed on a ceramic sheet 11, before a stacking process toform a body, during manufacturing an MLCC.

Referring to FIGS. 8A through 9B, forming an internal electrode and adielectric pattern in the process of manufacturing an MLCC may generallyinclude forming a ceramic sheet 11 on a jig 10, printing internalelectrodes 20 on a surface of the ceramic sheet 11, and printing adielectric pattern 30 between the printed internal electrodes 20 in alength direction X.

In an exemplary embodiment, forming the dielectric pattern 30 preciselyin a desired position may be an important factor in reducing a failurerate. Thus, as illustrated in FIG. 8A, the dielectric pattern 30 may berequired to be precisely formed between the internal electrodes 20, andwhen the dielectric pattern 30 is not accurately printed in a targetposition due to a manufacturing error, the dielectric pattern 30 may bebiased toward a side of one of the internal electrodes 20, asillustrated in FIG. 8B. As illustrated in FIG. 8B, when the dielectricpattern 30 is biased toward the one side of the one internal electrode20 between the internal electrodes 20, the dielectric pattern 30 may notbe in contact with the other internal electrode 20. Thus, a step portionproblem, caused by the internal electrodes 20, may not be solved.

The dielectric pattern 30 may have an overlap portion O, covering an endportion of the one internal electrode 20, to prevent the dielectricpattern 30 from being biased toward the one side of the one internalelectrode 20 between the internal electrodes 20 due to such amanufacturing error. Referring to FIGS. 9A and 9B, the dielectricpattern 30 may cover the end portions of the internal electrodes 20,thus solving the step portion problem caused by the internal electrodes20, even when precisely formed in a desired position as illustrated inFIG. 9A, as well as even when biased toward the one side of the oneinternal electrode 20 between the internal electrodes 20 due to such amanufacturing error as illustrated in FIG. 9B. Furthermore, thedielectric pattern 30 may have a thickness increased further than thatof the internal electrodes 20, thus preventing the internal electrodes20 from short-circuiting in the stacking direction due to the slippageof the internal electrodes 20 and the dielectric pattern 30 whenpressed. The present disclosure is not limited thereto. Although notshown in the drawings, the dielectric pattern may exactly fill the gapbetween the internal electrodes and physical contact with the internalelectrodes but not overlap with the internal electrodes, or thedielectric pattern may partially fill the gap between the internalelectrodes and be spaced apart from the internal electrodes. Suchconfigurations may still suppress the issue caused by the step portion,as compared to an example in which no dielectric pattern is disposed inthe gap between the internal electrodes.

Although not shown in the drawings, after stacking a plurality ofstructures shown in FIGS. 8A-9B, a body 110 may be formed by cutting thestacked structures along a path passing through a central portion of thedielectric pattern 30, such that the third surface 3 or the fourthsurface 4 of the body 110 is formed.

Thus, referring back to FIG. 3, the MLCC 100, according to an exemplaryembodiment, may have the first dielectric patterns 131 covering endportions of the first internal electrodes 121 and filling the firstspaces 121′, and the second dielectric patterns 132 covering endportions of the second internal electrodes 122 and filling the secondspaces 122′. The first dielectric patterns 131 may cover the endportions of the first internal electrodes 121 and fill the first spaces121′, and the second dielectric patterns 132 may cover the end portionsof the second internal electrodes 122 and fill the second spaces 122′,to solve a problem that the first and second dielectric patterns 131 and132 may not properly remove a step portion by being slipped whenpressed.

As a result, the MLCC, according to an exemplary embodiment, may havethe first and second internal electrodes 121 and 122 exposed to thefifth surface 5 and the sixth surface 6 to solve the step portionproblem caused by the margin portion, and may have the first and seconddielectric patterns 131 and 132 disposed in the first and second spaces121′ and 122′, that is, positions corresponding to the portion of thebody 110 in which only the first or second internal electrode 121 or 122is formed to solve the step portion problem caused by the portion of thebody 110.

Thus, the MLCC, according to an exemplary embodiment, may significantlyincrease BDV characteristics, as compared to an MLCC according to therelated art.

FIGS. 10A and 10B illustrate schematic plan views of a first internalelectrode 221 and a second internal electrode 222 of an MLCC accordingto another exemplary embodiment.

A description of the same configuration as that according to anexemplary embodiment will be omitted.

Referring to FIGS. 10A and 10B, the first internal electrode 221 of theMLCC according to another exemplary embodiment may include a firstcapacity portion 221 a and a first lead portion 221 b, and a secondinternal electrode 222 of the MLCC according to another exemplaryembodiment may include a second capacity portion 222 a and a second leadportion 222 b.

The first and second lead portions 221 b and 222 b may refer to portionsof the first and second internal electrodes 221 and 222, and may eachhave a width narrower than that of the first and second capacityportions 221 a and 222 a, and may each be connected to first and secondexternal electrodes.

As mentioned above, when the first and second internal electrodes 221and 222 are exposed to the fifth surface 5 and the sixth surface 6,short circuits caused by conductive foreign substances or delaminationof the cover layer may occur.

In the case of the fifth surface 5 and the sixth surface 6, the lateralinsulating layers may be disposed thereon to prevent short circuitscaused by conductive foreign substances. However, in the case of thethird surface 3 or the fourth surface 4, only a portion of the externalelectrode may be disposed thereon to cause a reduction in reliabilitydue to conductive foreign substances, such as the infiltration of waterinto the body.

To solve such a problem, the widths w_(a) and w_(b) of the first andsecond lead portions 221 b and 222 b may be controlled to 10% to 50% ofthe width w_(t) of the first and second capacity portions 221 a and 222a.

The following Table 1 illustrates measurements of high-temperature andhigh-humidity reliability evaluation and equivalent series resistance(ESR).

TABLE 1 High-Temperature and High-Humidity Reliability Samplew_(a)/w_(t), w_(b)/w_(t) Evaluation ESR (Mohm) 1 0 4 13.2 2 5 2 12.5 310 1 13.1 4 25 0 13.3 5 50 0 13.5 6 60 2 15.0

For the high-temperature and high-humidity reliability evaluation, waterabsorption reliability according to the ratios w_(a)/w_(t) andw_(b)/w_(t) of the widths w_(a) and w_(b) of the first and second leadportions 221 b and 222 b to the width w_(t) of the first and secondcapacity portions 221 a and 222 a was measured by measuring levels ofresistance of 100 chips over time under high-temperature andhigh-humidity conditions and calculating the number of chips whoselevels of resistance dropped sharply.

Referring to Table 1, when the widths w_(a) and w_(b) of the first andsecond lead portions 221 b and 222 b are less than 10% of the widthw_(t) of the first and second capacity portions 221 a and 222 a, theeffect of increasing high-temperature and high-humidity reliability maybe low. In contrast, when the widths w_(a) and w_(b) of the first andsecond lead portions 221 b and 222 b are greater than 50% of the widthw_(t) of the first and second capacity portions 221 a and 222 a, areduction in contact areas between the external electrodes and the firstand second internal electrodes 221 and 222 may cause ESR to increase.

Thus, the MLCC, according to another exemplary embodiment, may allow thewidths w_(a) and w_(b) of the first and second lead portions 221 b and222 b to be controlled to 10% to 50% of the width w_(t) of the first andsecond capacity portions 221 a and 222 a, thus preventing short circuitscaused by conductive foreign substances. Alternatively, the MLCC,according to another exemplary embodiment, may allow the widths w_(a)and w_(b) of the first and second lead portions 221 b and 222 b to becontrolled to greater than 10% but equal to or less than 50% of thewidth w_(t) of the first and second capacity portions 221 a and 222 a,to significantly increase high-temperature and high-humidityreliability.

When the widths w_(a) and w_(b) of the first and second lead portions221 b and 222 b are narrower than that of the first and second capacityportions 221 a and 222 a, areas in which the first and second internalelectrodes 221 and 222 are not formed may be generated in first andsecond dielectric layers 211 a and 211 b. For example, a step portionmay be formed due to a difference between the thicknesses of the firstand second internal electrodes 221 and 222 on points on which the firstand second lead portions 221 b and 222 b meet the first and secondcapacity portions 221 a and 222 a. For example, the step portion, formedon the points on which the first and second lead portions 221 b and 222b meet the first and second capacity portions 221 a and 222 a, may causethe dielectric layers and the first and second internal electrodes 221and 222 to be elongated when the dielectric layers are stacked andpressed. Accordingly, BDV characteristics may deteriorate in curvedportions of the first and second internal electrodes 221 and 222.

Thus, a third dielectric pattern 233 may be disposed on the point atwhich the first capacity portion 221 a meets the first lead portion 221b, and a fourth dielectric pattern 234 may be disposed on the point atwhich the second capacity portion 222 a meets the second lead portion222 b, solving the step portion problem. For example, the thirddielectric pattern 233 may be exposed to the third surface 3, and may bedisposed on the point at which the first capacity portion 221 a and thefirst lead portion 221 b of the first dielectric layer 211 a may be incontact with each other. Further, the fourth dielectric pattern 234 maybe exposed to the fourth surface 4, and may be disposed on the point atwhich the second capacity portion 222 a and the second lead portion 222b of the second dielectric layer 211 a may be in contact with eachother. The third and fourth dielectric patterns 233 and 234 may have theabove-mentioned dielectric patterns that may be sintered at the lowtemperature, thus increasing sinterability of portions of the MLCCcorresponding to the third and fourth dielectric patterns 233 and 234.

Further, the MLCC, according to another exemplary embodiment, mayinclude first and second dielectric patterns 231 and 232 as in anexemplary embodiment. The first through fourth dielectric patterns 231through 234 may be made of the same material used to form the dielectricpatterns 131 and 132 and may be different from that is used to make thedielectric layers in the MLCC according to another exemplary embodiment.

Board Having Multilayer Ceramic Capacitor

FIG. 11 illustrates a schematic perspective view of a board 1000 havingan MLCC according to another exemplary embodiment.

Referring to FIG. 11, the board 1000 of the MLCC according to anotherexemplary embodiment may include a substrate 1100, first and second pads1201 and 1202, and an MLCC 100.

The substrate 1100 may be a printed circuit board (PCB), but the presentdisclosure is not limited thereto. The first and second pads 1201 and1202 may be disposed on a surface of the substrate 1100. The first pad1201 may be connected to a first external electrode 151, and the secondpad 1202 may be connected to a second external electrode 152.

The MLCC 100, mounted on the board 1000 of the MLCC according to anotherexemplary embodiment, may include the MLCC 100 according to variousexemplary embodiments described in the present disclosure.

For example, the MLCC 100, mounted on the board 1000 of the MLCCaccording to another exemplary embodiment may include: as illustrated inFIGS. 1 through 4, the body 110 including the first and seconddielectric layers 111 a and 111 b, the body including the first surface1 and the second surface 2 opposing each other in the stackingdirection, the third surface 3 and the fourth surface 4 connected to thefirst surface 1 and the second surface 2 and opposing each other, andthe fifth surface 5 and the sixth surface 6 connected to the first tofourth surfaces 1 to 4 and opposing each other; the first internalelectrodes 121 disposed on the first dielectric layers 111 a, exposed tothe third surface 3, the fifth surface 5, and the sixth surface 6, andspaced apart from the fourth surface 4 by the first spaces 121′; thesecond internal electrodes 122 disposed on the second dielectric layers111 b to oppose the first internal electrodes 121 with the firstdielectric layers 111 a or the second dielectric layers 111 b interposedtherebetween, exposed to the fourth surface 4, the fifth surface 5, andthe sixth surface 6, and spaced apart from the third surface 3 by thesecond spaces 122′; the first dielectric patterns 131 disposed in the atleast a portion of the first spaces 121′, and the second dielectricpatterns 132 disposed in the at least a portion of the second spaces122′; and the lateral insulating layers 140 disposed on the fifthsurface 5 and the sixth surface 6 of the body 110. The MLCC 100 may besubstituted by an MLCC according to another exemplary embodimentdescribed with reference to FIGS. 10A and 10B.

As set forth above, according to an exemplary embodiment, a multilayerceramic capacitor (MLCC) may have first and second internal electrodesexposed to a fifth surface and a sixth surface to prevent a step portionfrom being formed by the first and second internal electrodes on bothend surfaces of a body in a width direction, and may include first andsecond dielectric patterns compensating for step portions formed on bothend portions of the first and second internal electrodes in a lengthdirection to prevent a step portion from being formed by the first andsecond internal electrodes on both end surfaces of the body in a lengthdirection, thus increasing reliability of the MLCC.

While exemplary embodiments have been shown and described above, it willbe apparent to those skilled in the art that modifications andvariations could be made without departing from the scope of the presentdisclosure, as defined by the appended claims.

What is claimed is:
 1. A multilayer ceramic capacitor (MLCC), comprising: a body including first dielectric layers and second dielectric layers, the body including a first surface and a second surface opposing each other in a stacking direction along which the first and second dielectric layers are stacked, a third surface and a fourth surface connected to the first surface and the second surface and opposing each other, and a fifth surface and a sixth surface connected to the first surface, the second surface, the third surface, and the fourth surface and opposing each other; first internal electrodes disposed on the first dielectric layers, exposed to the third surface, the fifth surface, and the sixth surface, and spaced apart from the fourth surface by first spaces; second internal electrodes disposed on the second dielectric layers to oppose the first internal electrodes with the first dielectric layers or the second dielectric layers interposed therebetween, exposed to the fourth surface, the fifth surface, and the sixth surface, and spaced apart from the third surface by second spaces; first dielectric patterns disposed in at least portions of the first spaces to contact respective side surfaces of the first internal electrodes, and extending from the side surfaces to cover portions of upper surfaces of the first internal electrodes, respectively, the side surfaces of the first internal electrodes connecting the upper surfaces of the first internal electrodes to lower surfaces of the first internal electrodes, respectively; second dielectric patterns disposed in at least portions of the second spaces to contact respective side surfaces of the second internal electrodes, and extending from the side surfaces to cover portions of upper surfaces of the second internal electrodes, respectively, the side surfaces of the second internal electrodes connecting the upper surfaces of the second internal electrodes to lower surfaces of the second internal electrodes, respectively; and lateral insulating layers disposed on the fifth surface and the sixth surface of the body.
 2. The MLCC of claim 1, wherein the first spaces are completely filled with the first dielectric patterns, respectively, and the second spaces are completely filled with the second dielectric patterns, respectively.
 3. The MLCC of claim 1, wherein a deformation angle of the first internal electrodes is 15° or lower, the deformation angle being an angle of each portion of the first internal electrodes exposed to the third surface inclined with respect to the second surface.
 4. The MLCC of claim 1, wherein the first dielectric patterns and the second dielectric patterns include a dielectric able to be sintered at a temperature lower than that for sintering the first and second dielectric layers.
 5. The MLCC of claim 1, wherein each of the first internal electrodes includes a first capacity portion and a first lead portion connecting the first capacity portion to a first external electrode while having, a width narrower than a width of the first capacity portion.
 6. The MLCC of claim 5, wherein a ratio of the width of the first lead portion to the width of the first capacity portion is 10% to 50%.
 7. The MLCC of claim 5, further comprising third dielectric patterns disposed on portions of the first dielectric layers in which the first capacity portion is in contact with they first lead portion.
 8. The MLCC of claim 7, wherein the third dielectric patterns include a dielectric, the dielectric including a low-temperature-sintered material having a glass component containing an alkali metal.
 9. The MLCC of claim 1, wherein the first and second dielectric patterns include a dielectric, the dielectric including a low-temperature-sintered material having a glass component containing an alkali metal.
 10. The MLCC of claim 1, wherein the first and second dielectric patterns are made of a material different from that is used to make the first and second dielectric layers.
 11. The MLCC of claim 1, wherein the first dielectric patterns and the second dielectric patterns are exposed to the fifth and sixth surfaces and are in contact with the lateral insulating layers.
 12. The MLCC of claim 1, wherein the lateral insulating layers include a polymer or a ceramic.
 13. The MLCC of claim 1, wherein the lateral insulating layers include a dielectric.
 14. A board having a multilayer ceramic capacitor (MLCC), the board comprising: a substrate having a first pad and a second pad disposed on a surface thereof; and the MLCC of claim 1 mounted on the substrate.
 15. A multilayer ceramic capacitor (MLCC), comprising: a body including first dielectric layers and second dielectric layers, the body including a first surface and a second surface opposing each other in a stacking direction along which the first and second dielectric layers are stacked, a third surface and a fourth surface connected to the first surface and the second surface and opposing each other, and a fifth surface and a sixth surface connected to the first surface, the second surface, the third surface, and the fourth surface and opposing each other; first internal electrodes disposed on the first dielectric layers, exposed to the third surface, and spaced apart from the fourth surface by first spaces; second internal electrodes disposed on the second dielectric layers to oppose the first internal electrodes with the first dielectric layers or the second dielectric layers interposed therebetween, exposed to the fourth surface, and spaced apart from the third surface by second spaces; first dielectric patterns disposed in portions of the first spaces to contact respective side surfaces of the first internal electrodes, and extending from the side surfaces to cover portions of upper surfaces of the first internal electrodes, respectively, the side surfaces of the first internal electrodes connecting the upper surfaces of the first internal electrodes to lower surfaces of the first internal electrodes, respectively; second dielectric patterns disposed in portions of the second spaces to contact respective side surfaces of the second internal electrodes, and extending from the side surfaces to cover portions of upper surfaces of the second internal electrodes, respectively, the side surfaces of the second internal electrodes connecting the upper surfaces of the second internal electrodes to lower surfaces of the second internal electrodes, respectively; and a first external electrode and a second external electrode disposed on the third surface and the fourth surface and electrically connected to the first internal electrodes and the second internal electrodes, respectively.
 16. The MLCC of claim 15, wherein the first and second dielectric patterns are made of a material different from that is used to make the first and second dielectric layers.
 17. The MLCC of claim 15, wherein the first spaces are completely filled with the first dielectric patterns, respectively, and the second spaces are completely filled with the second dielectric patterns, respectively.
 18. The MLCC of claim 15, wherein a deformation angle of the first internal electrodes is 15° or lower, the deformation angle being an angle of each portion of the first internal electrodes exposed to the third surface inclined with respect to the second surface.
 19. The MLCC of claim 15, wherein each of the first internal electrodes includes a first capacity portion and a first lead portion connecting the first capacity portion to a first external electrode while having a width narrower than a width of the first capacity portion, and the MLCC further comprises third dielectric patterns disposed on portions of the first dielectric layers in which the first capacity portion is in contact with the first lead portion.
 20. The MLCC of claim 15, wherein the first internal electrodes are exposed to the fifth surface and the sixth surface, and the second internal electrodes are exposed to the fifth surface and the sixth surface, and the MLCC further comprises lateral insulating layers disposed on the fifth surface and the sixth surface of the body.
 21. The MLCC of claim 20, wherein the first dielectric patterns and the second dielectric patterns are exposed to the fifth and sixth surfaces and are in contact with the lateral insulating layers.
 22. A multilayer ceramic capacitor (MLCC), comprising: a body including first dielectric layers and second dielectric layers, the body including a first surface and a second surface opposing each other in a stacking direction along which the first and second dielectric layers are stacked, a third surface and a fourth surface connected to the first surface and the second surface and opposing each other, and a fifth surface and a sixth surface connected to the first surface, the second surface, the third surface, and the fourth surface and opposing each other; first internal electrodes disposed on the first dielectric layers, exposed to the third surface, the fifth surface, and the sixth surface, and spaced apart from the fourth surface by first spaces; second internal electrodes disposed on the second dielectric layers to oppose the first internal electrodes with the first dielectric layers or the second dielectric layers interposed therebetween, exposed to the fourth surface, the fifth surface, and the sixth surface, and spaced apart from the third surface by second spaces; first dielectric patterns disposed in at least a portion of the first spaces, and second dielectric patterns disposed in at least a portion of the second spaces; and lateral insulating layers disposed on the fifth surface and the sixth surface of the body, wherein a thickness, in the stacking direction, of one of the first dielectric patterns is greater than a thickness, in the stacking direction, of one of the first internal electrodes, the one of the first dielectric patterns and the one of the first internal electrodes disposed on a same one of the first dielectric layers, a thickness, in the stacking direction, of one of the second dielectric patterns is greater than a thickness, in the stacking direction, of one of the second internal electrodes, the one of the second dielectric patterns and the one of the second internal electrodes disposed on a same one of the second dielectric layers, and the first dielectric patterns overlap end portions of the first internal electrodes in the stacking direction and fill the first spaces, respectively, and the second dielectric patterns overlap end portions of the second internal electrodes in the stacking direction and fill the second spaces, respectively.
 23. The MLCC of claim 22, wherein a deformation angle of the first internal electrodes is 15° or lower, the deformation angle being an angle of each portion of the first internal electrodes exposed to the third surface inclined with respect to the second surface.
 24. The MLCC of claim 22, wherein the first dielectric patterns and the second dielectric patterns include a dielectric able to be sintered at a temperature lower than that for sintering the first and second dielectric layers.
 25. The MLCC of claim 22, wherein each of the first internal electrodes includes a first capacity portion and a first lead portion connecting the first capacity portion to a first external electrode while having a width narrower than a width of the first capacity portion.
 26. The MLCC of claim 25, wherein a ratio of the width of the first lead portion to the width of the first capacity portion is 10% to 50%.
 27. The MLCC of claim 25, further comprising third dielectric patterns disposed on portions of the first dielectric layers in which the first capacity portion is in contact with the first lead portion.
 28. The MLCC of claim 27, wherein the third dielectric patterns include a dielectric, the dielectric including a low-temperature-sintered material having a glass component containing an alkali metal.
 29. The MLCC of claim 22, wherein the first and second dielectric patterns include a dielectric, the dielectric including a low-temperature-sintered material having a glass component containing an alkali metal.
 30. The MLCC of claim 22, wherein the first and second dielectric patterns are made of a material different from that is used to make the first and second dielectric layers.
 31. The MLCC of claim 22, wherein the first dielectric patterns and the second dielectric patterns are exposed to the fifth and sixth surfaces and are in contact with the lateral insulating layers.
 32. The MLCC of claim 22, wherein the lateral insulating layers include a polymer, a ceramic, or a dielectric. 